Mining apparatus



April 5, 1966 MINING APPARATUS 2 Sheets-Sheet 1 Filed April 15, 1963 m a2, s s m m Mm H mz i J N13 1 vo bm E 95 6 n1 1 5 Wm m w. L1 t Iv:itl::Iuf: M M H F .1 iii; x viz ET L, L m1 519m N 21 2% -92 N B N0 2 z 05 a g g Q i n an RV./ L: E :mm :mw NW NW .w :E ;H@ f doc 33% Q3 5 a WM 0m h n m 5 7!: A O n April 1966 D. G. A. THOMAS ETAL 3,243,964

MINING APPARATUS 2 Sheets-Sheet 2 Filed April 15, 1963 mu 7 +6 I. C 2 QA C 3 K11 T O "O b 2 m k Mu Ba 11 x A m @H INvENTafis PAW G,A- 77/oMA5.1- TMES GARNEGIE' M! M United States Patent O 3,243,964 MININGAPPARATUS David Gurney Arnold Thomas, Derhurst, and James Carnegie,(Zheltenham, England, assignors to Dowty Technical Developments Limited,Brockhampton Park, near Andoversford, England, a British company FiledApr. 15, 1963, Ser. No. 272,913 9 Claims. (Cl. 61-45) This inventionrelates to mining apparatus.

In a mine, for example a coal mine, it is usual to arrange a series ofroof supports along the working face of the mine and to advance the roofsupports periodically towards the working face.

This invention relates to such mining apparatus in which the roofsupports advance automatically in a predetermined sequence and each roofsupport is able to advance only when a predetermined signal has beenobtained from the previous roof support in the sequence. Such a signalis preferably obtained from a support only when the support hassatisfactorily completed its advancing operation, that is to saysatisfactorily supports the roof at a position which is advanced towardsthe working face relative to the position of the roof support before theadvancing operation began. A roof support which has failed to give apredetermined signal will be referred to as a failed roof support.

Circumstances causing a roof support to fail may be, for example, anyone or more of the following:

(a) The roof support has failed to advance because of a fault in theadvancing means associated with the support, or because a step in thefloor of the mine prevents the advance, or because a conveyor, situatedbetween the series of roof supports and the working face and whichshould have been advanced previously, has not advanced and thereforeobstructs the advance of the roof support.

(b) The roof support has failed to satisfactoriiy support the roof afterits advance because of a fault in the support extending means, because ahole has occurred in the roof above the support and the support hasextended to its maximum height without satisfactorily supporting theroof.

Failure to receive the signal from a roof support causes the advance ofthe roof supports to stop, and it is an object of the present inventionto provide an improved mining apparatus in which the advance of the roofsupports need not necessarily cease until the fault causing the stoppagehas been found and rectified.

The present invention provides mining apparatus including a series ofroof supports arranged along the working face of a mine, means forautomatically advancing the roof supports towards the working face in apredetermined sequence, each roof support being advanced after apredetermined signal has been obtained from the preceding support in thesequence, override means for causing the automatic-advancing means toemit a failed roof support from the sequence, and safety meansresponsive to selection of the override means and arranged to indicate apredetermined number of selections of the override means.

The safety means may indicate a predetermined number of selections ofthe override means corresponding to a predetermined number of failedroof supports randomly situated in the sequence, that is to say thesafety means will indicate when a predetermined number of roof supportshave failed, regardless of where they are situated in the sequence. Thesafety means may include a series of electrical relay circuits which aresuccessively operated when each successive override operation isselected, the relay circuit corresponding to the override selectionmaking up the predetermined number being arranged, when actuated tooperate an indicating means.

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The safety means may indicate a predetermined number of selections ofthe override means corresponding to a predetermined number of failedsupports adjacently situated in the sequence. For example, the safetymeans may indicate the failure of any two adjacent roof supports. Thesafety means may include an electrical relay circuit which is operatedby the selection of the override means following failure of a roofsupport in the sequence and which is reset by the attainment of asatisfactory advancing operation of the next support in the sequence.

The safety means may indicate a predetermined number of selections ofthe override means by preventing any further override operations.Alternatively, or additionally, the safety means may indicate apredetermined number of selections of the override means by preventingfurther automatic advance of the roof supports.

One embodiment of the present invention will now be described, by Way ofexample, with reference to the accompanying drawings, of which,

FIGURE 1 is a diagrammatic view of a mining apparatus,

FIGURE 2 is an electrical circuit diagram of one part of the safetymeans, and,

FIGURE 3 is an electrical circuit diagram of another part of the safetymeans.

With reference to the accompanying drawing, a mining apparatus includesa series of roof supports 1 arranged along the working face 2 of a coalmine. A conveyor 3 extends along the coal face in front of the roofsupports 1 and a cutting machine 4 is located in front of the conveyor3. In the drawing, the cutting machine 4 is moving from left to right.

Each roof support 1 includes a floor beam carrying two or morehydraulically-operable props 5 which carry a roof beam 6. Each roofsupport 1 is connected to the conveyor 3 by a hydraulically-operablejack 7 by means of which the roof support can be advanced up to theconveyor 3. At least some of the jacks 7 may be doubleacting so that theconveyor 3 can be advanced relative to the roof supports 1.Alternatively, additional jacks may be secured between the roof support1 and the conveyor 3 for advancing the conveyor 3.

The roof supports 1 are advanceable automatically towards the workingface in a predetermined sequence. In this case each roof support isadvanced successively, starting at the left hand end of the series.Means for automatically advancing the roof supports 1 includes anelectro-hydraulic valve assembly (not shown) secured to each roofsupport. Each valve assembly can be electrically actuated to cause theprops 5 to collapse thus lowering the support from the roof, the jack 7to contract and ad- Vance the support towards the conveyor, 3, and thenthe props 5 to reset the support against the roof. When a satisfactoryhydraulic pressure has built up in the props 5 after the support hasbeen reset, this pressure causes a predetermined hydraulic-pressuresignal to be emitted from the support.

Hydraulic fluid supply and return lines (not shown) extend along theface from a source of hydraulic fluid under pressure and are connectedto the props 5 and jack 7 of each roof support 1.

The automatic advancing means also includes an automati'c-advancecontrol 8 connected to each roof support 1 by wires 9. Theautomatic-advance control 8 is an electrical control and can send anelectrical signal along the Wires 9 to the valve assembly of each roofsupport in turn to cause the roof support to undergo an advancingoperation. A signal is not sent by the automatic-advance control 8 to aroof support until a predetermined hydraulicpressure signal, whichindicates satisfactory completion of an advancing operation, has beenreceived by the auto- 3 matic-advance control 8 along the wires 9 fromthe previous roof support in the sequence.

A mining apparatus as so far described has been more fully described inUnited Kingdom patent application No. 41622/61.

If .the signal is not received by the automatic-advance control 8 from aroof support 1 in the sequence, the automatic .advance of the roofsupports 1 will stop. The min ing apparatus includes override means 11for causing the automatic-advance means 8 to omit a failed roof supportfrom the sequence. The override means 11 is manually operable andoperation of the override means 11 sends an electric signal to theautomatic-advance control 8 to cause the control 8 to select the nextroof support in the sequence for advance without having received asignal from the failed roof support. 7 The mining apparatus furtherincludes safety means 12 responsive to the selection of the overridemeans and arranged to indicate a predetermined number of selections ofthe override means 11. p

One part of the safety means 12 is shown in FIGURE 2 and this partindicates a predetermined number of selections of the override means 11corresponding to a predetermined number of failed roof supports randomlysituated in the sequence, that is to say the part of the safety means 12shown in FIGURE 2 indicates when a predetermined number of roof supportshave failed, regardless of ,where they are situated inthe sequence. Thepart includes a series of electrical relay circuits N, O, V. Each relayhas four associated contacts N1, N2, N3, N4, etc. FIGURE 2 shows thepositions of the contacts when the relays are in the de-energisedcondition.

Contact 01 is actually made up of three sub-contacts a, b, and c. Whenrelay solenoid is in the de-energised condition, contact a engagescontact [1, and contact c is isolated. This condition of contact 01 isreferred to as the open condition. When relay solenoid is energised,contact engages contact a and then disengages contact a from contact b.This condition of contact 01 is referred to as the closed condition.Contacts P1, Q1, V1 and N4 are similarly constructed.

Relay solenoids are connected in parallel with each other between a DOsupply, the positive line being line 14 and the negative line being line15. Relay solenoids are also connected in parallel with each otherbetween line 15 and a line 16. Line 16 includes a normally open switchS2 and is connected to the DC. positive supply. Switch S2 is associatedwith the override means 11 and, when an override operation is selectedby actuations of the override means 11, switch S2 is closed.

The line 14 includes a reset switch S1 which normally closes the line 14but which can be operated to first connect line 17 to the DO. positivesupply and then break the line 14. The line 17 is connected to relaysolenoid The various relay contacts are arranged as shown in FIGURE 2.For example, between relay solenoid and line 16 are contacts 03 and N3which are in series with each other and in parallel with contact P2 andsubcontacts'a and c of contact Q1. Contact P2 and subcontacts a and c ofcontact Q1 are in series with each other. Contact P2 and sub-contacts aand b of contact Q1 are connected in series with each other betweenrelay solenoid solenoid when the circuit through it is broken, and sorender the circuit safe for use in a mine. The rectifiers connectedbetween line 14 and the relay contacts and between line 16 and the relaycontacts prevent unwanted interconnections which may otherwise occur.

The circuit also includes a rotary switch S3 by means of which thepredetermined number of override selections which the circuit indicatescan be varied. A rotary arm 18 can be rotated to contact any one ofeight lines 19. Each line 19 is connected to a different one of therelay solenoids In FIGURE 2, the rotary arm 18 is contacting the line.19 connected to relay solenoid and, as will be described later, thismeans that the circuit will indicate when three override selections havebeen made.

An indicating means includes a relay solenoid connected between line 15and the rotary arm 18 and controlling three contacts W1, W2, and W3which are normally open but which close when relay solenoid isenergised. Contact W1 is located in a warning circuit which contains,for example, a warning lamp or audible device, contact W2 is located ina circuit in the "automatic advance means 8, and contact W3 is locatedin a circuit in the override means 11.

In operation, reset switch S1 is switched to close line 17 and open line.14. This energises relay solenoid through line 17 and ensures that allthe other relays are in t e de-en glsed condition. Energisation of relaysolenoid closes contacts N1, N2 and N4 and opens contact N3. SWltCh S1is then switched to close line 14 and open line 17. The relay solenoidholds on through contact N1 and line 14.

If a roof support fails, the operator selects an operation of theoverride means 11 and consequently temporarily closes switch S2. Acircuit is then completed to relay solenoid through contacts U1 and N2,and relay solenoid is energised. Energisation of relay solenoid causessub-contacts a and c of contact 01 to close and sub-contacts a and b ofcontact 01 to open, thus deenergising relay solenoid Also contacts 02and 03 close and contact 04 opens.

De-energisation of relay solenoid opens contacts N1, N2 and N4 andcloses contact N3. Thus relay solenoid holds on through 02 and line 14,and it will be seen that closure of contacts N3 and O3 prepares acircuit to relay solenoid In a similar manner, a second overrideselection energises relay solenoid de-energises relay solenoid andprepares a circuit to relay solenoid When a third override selection ismade, a circuit is completed through line 16, contacts 04 and P3 and therelevant line 19 to relay solenoid which is therefore actuated to closecontacts W1, W2 and W3. Thus the warning lamp or audible deviceoperates, further automatic-advance of the supports is prevented andfurther override selection is prevented.

The advancing sequence can only be restarted by resetting the circuit bymeans of reset switch S1 and this switch is preferably operable only byoperation of a lock and key device.

The part of the safety means 12 described with reference to FIGURE 2indicates when a predetermined member of override selectionscorresponding to a predetermined member of randomly situated roofsupports has been made. Alternatively or additionally, it may bedesirable to provide safety means which indicates when a predeterminednumber of adjacent roof supports have failed. The part of the safetymeans 12 now to be described with reference to FIGURE 3 indicates whentwo adjacent roof supports have failed.

The part of the safety means 12 shown in FIGURE 3 includes three relaysA, B and C connected in parallel with one another between a DC. supply.In the line between relay solenoid and the positive supply line are twoswitches PS and SS. Switch SS is closed by the selection of resetting ofthe props of a roof support and switch P5 is closed by the attainment ofa satisfactory hydraulic pressure in the props after a roof support hasbeen reset against the roof.

Relay solenoid can be connected to the positive supply line by any oneof three possible paths. The first path includes normallyopen contactAl, the second path includes normally-open contacts B1, and subcontactsa and c of contact C2, and switch S2. Switch S2 is a switch which isclose-d by selection of an override operation. The third path includesnormally-open contact B1 and normally-closed sub-contacts a and b ofcontact C2. Relay solenoid can be connected to the positive supply lineby two possible paths, one path including normally-open contact S2 andthe other path including normally-open contact C1 and normally-closedcontact A2.

A warning lamp 21 is connected between the negative and positive supplylines, the path between the lamp and positive including normally-opencontact C3. Relay C may also include a further contact which when closedpresents further operation of the automatic-advance control 8, in amanner similar to that described with reference to FIGURE 2.

FIGURE 3 also shows a fragment of the circuit of the override means 11.Switch S4 is the override selection switch which is ganged to switch S2and B2 is a normallyopen contact controlled by relay solenoid Inoperation of the circuit shown in FIGURE 3, if a roof support resetssatisfactorily against the roof, switches PS and SS are closed and relaysolenoid is energised. Thus contact A1 closes to energise relay solenoidand contact A2 opens. Contacts B1 and B2 close. Relay B then holds onthrough contact B1 and sub-contacts a and b of contact C2. Closure ofcontact B2 thus prepares the circuit of the override means 11.

If the next roof support in the sequence resets satisfactorily againstthe roof to energise relay solenoid contacts PS and SS again close butrelay solenoid is already energised.

If the next roof support in the sequence fails, at least contact PS doesnot close and relay solenoid is not energised. Thus contact A1 remainsopen and contact A2 remains closed. The override means is then operatedby closing switch S4, which causes closure of switch S2. Thus relaysolenoid is energised and holds on through contacts C1 and A2. C2 alsocloses to break contact between sub-contacts a and b and make contactbetween sub-contacts a and c. Consequently when contact S2 opens, relaysolenoid is de-energised and contacts B1 and B2 open. Further, closureof contact C3 causes the warning lamp to operate and further advance ofthe support to be prevented.

Since contact B2 is open, the override means cannot 'be operated againif the next roof support fails, since cannot be energised. Also, if thenext roof support fails, the Warning lamp remains on. If the next roofsupport advances and resets satisfactorily however, relay solenoid A Band 2 2 are once more energised with the result that relay solenoid C isde-mergised (thus extinguishing the warning lamp) and contact B2 closesto prepare the circuit of the override means.

After a failure of a roof support therefore, the circuit of FIGURE 3 isonly reset if the neXt roof support in the sequence satisfactorilycompletes its advancing operation.

Thus the circuit of FIGURE 3 indicates when two adjacent roof supportshave failed by causing the Warning lamp to remain illuminated andpreventing the second failed roof support from being overridden, as wellas preventing further operation of the automatic-advance means.

We claim as our invention:

1. Mining apparatus including a series of roof supports arranged alongthe working face of a mine and each providing a predetermined signalupon reaching asatisfactory roof supporting condition, automaticadvancing means automatically advancing the roof supports towards theworking face in a predetermined sequence in response to successivepredetermined signals from adjacent supports in sequence, override meansselectively operating to cause said automatic-advancing means to omit afailed roof support from said sequence, and safety means responsive toeach operation of said override means indicating the occurrence of apredetermined number of operations of said override means.

2. Mining apparatus according to claim 1 wherein said safety meansincludes means indicating a predetermined number of operations of theoverride means corresponding to a predetermined number of failedsupports randomly situated in said sequence.

3. Mining apparatus according to claim 2 wherein said safety meansincludes a series of electrical relay circuit means connected to besuccessively operated in response to each successive operation of saidoverride means and including indicating circuit means coupled with aselected one of said series of relay circuit means and operable uponoperation of said selected one to provide an indication that saidpredetermined number of operations of said override means has occurred.

4. Mining apparatus according to claim 1, wherein said safety meansincludes means indicating a predetermined number of selections of theoverride means corresponding to a predetermined number of failedsupports adjacently situated in sequence. i

5. Mining apparatus according to claim 4 wherein said safety meansincludes electrical relay circuit means operated by the operation ofsaid override means upon failure of a support in a sequence, and resetin response to a satisfactory advancing operation of the next succeedinsupport in said sequence.

6; Mining apparatus according to claim 1 wherein sairl safety meansincludes means responsive to a predetermined number of operations ofsaid override means'to prevent any further override operations.

7. Mining apparatus according to claim 1 wherein said safety meansincludes means responsive to a predetermined number of operations ofsaid override means to prevent further automatic advance of said roofsupports.

8. A mining apparatus comprising in combination: a plurality of roofsupports each providing a first signal upon achieving a predeterminedfirst condition; roof support advancing means responsive only to saidfirst signals occurring in a selected sequence to cause sequentialadvancement of said supports to said first condition; override meanscoupled with said advancing means and selectively operating to continueoperation of said advancing means for sequential support advancementwhen one of said first signals in said selected sequence is not receivedby said advancing means; and safety means coupled with said overridemeans providing an indication of the occurrence of a predeterminednumber of operations of said override means, whereby a warning isprovided when a number of roof supports equal to said predeterminednumber have failed to achieve said first condition.

9. A mining apparatus in accordance with claim 8 wherein said safetymeans includes: a plurality of relays connected in circuit forsequential energization in response to repeated operation of saidoverride means; indicating means; and switch means connected to saidindicating means and to said relays and selectively adjustable toconnect said indicating means in circuit with a selected one of saidrelays, whereby said indicating means is energized upon energization ofa selected one of said relays.

References (Zited by the Examiner FOREIGN PATENTS 877,995 9/1961 GreatBritain.

CHARLES 'E. OCONNELL, Primary Examiner.

EARL J. WITMER, Examiner. R. A. STENZEL, Assistant Examiner.

1. MINING APPARATUS INCLUDING A SERIES OF ROOF SUPPORTS ARRANGED ALONGTHE WORKING FACE OF A MINE AND EACH PROVIDING A PREDETERMINED SIGNALUPON REACHING A SATISFACTORY ROOF SUPPORTING CONDITION, AUTOMATICADVANCING MEANS AUTOMATICALLY ADVANCING THE ROOF SUPPORTS TOWARDS THEWORKING FACE IN A PREDETERMINED SEQUENCE IN RESPONSE TO SUCCESSIVEPREDETERMINED SIGNALS FROM ADJACENT SUPPORTS IN SEQUENCE, OVERRIDE MEANSSELECTIVELY OPERATING TO CAUSE SAID AUTOMATIC-ADVANCING MEANS TO OMIT AFAILED ROOF SUPPORT FROM SAID SEQUENCE, AND SAFETY MEANS RESPONSIVE TOEACH OPERATION OF SAID OVERRIDE MEANS INDICATING THE OCCURRENCE OF APREDETERMINED NUMBER OF OPERATIONS OF SAID OVERRIDE MEANS.